Various processes suited to render polymers fireproof are known in the art. Such processes are generally based on the use of metal compounds, particularly of antimony, in combination with heat-unstable halogenated compounds, such as, for example, chlorinated paraffin waxes.
The metal compound + halogenated compound combinations provide satisfactory results as regards the self-extinguishing properties they impart to the polymers, but they exhibit serious drawbacks, namely, corrosion phenomena in the machinery where the materials are processed and a strong evolution of toxic fumes and gases in case of fires. Furthermore, acceptable levels of self-extinguishing power are attained only by employing high concentrations of such combinations.